Manchester United flop Shinji Kagawa has completed his return to Borussia Dortmund for £6.3million - just two years after leaving the German side.

Kagawa will sign a four year contract with the Dortmund, who sold the Japanese playmaker to United in 2012 for £12million.

But injuries have stunted the midfielders progress, and after failing to fit into David Moyes' side last season, he has now been deemed surplus to requirements by new manager Louis van Gaal.

VIDEO Dortmund-bound Shinji Kagawa takes the Ice Bucket Challenge

Return: Borussia Dortmund have re-signed midfielder Shinji Kagawa from Manchester United for £6.3m

Welcome home! Dortmund welcomed Kagawa back on Twitter with this picture from his previous spell

Surplus to requirements: Manchester United have let Kagawa return to Germany after two years at Old Trafford

Kagawa was welcomed back to Dortmund by the club on Twitter with a picture of manager Jurgen Klopp running towards the playmaker during his previous spell at the club.

The picture was accompanied by ‘帰ってきた！#wiederhier #backhome’ – with welcome home written in Japanese and German for their Twitter followers.

Following two disappointing years in Manchester and only 38 appearances, Kagawa is determined to write a new chapter back in Dortmund.

Summer signing: Sir Alex Ferguson (centre) signed Kagawa (left) from Dortmund in July 2012 for £12million

Better times: Shinji Kagawa is returning to the club where he impressed during his first two years in Europe

He said, ‘The day I left, I said in an interview that the chapter Borussia Dortmund was not closed in my life. I wanted to fulfill my dream of playing in the Premier League.

‘Now I am simply delighted to be back in Dortmund with this fantastic team and set-up and these unique fans.

‘BVB is like a family and I am proud that they did not forget me and that I can belong to it once more", said Kagawa.

Hampered: Kagawa leaves the field with an injury, as was so often the case during his time at Old Trafford

Dortmund manager Jurgen Klopp repeatedly made it clear Kagawa would be welcomed back with open arms, and got his wish after an unhappy spell at Old Trafford for the attacking midfielder.

When it became clear chances would continue to be limited under current manager Louis van Gaal, Dortmund seized their chance to lure him back to the Westfalenstadion.

Spanish side Valencia were also interested in the Japan captain, but Kagawa wanted to return to the club where he made his name in European football.

'The possibility of signing Shinji Kagawa from Manchester United only arose for the first time in the last few days', said Borussia Dortmund sporting director Michael Zorc, adding 'Naturally we decided to add his enormous quality to our squad once again.'

Tough time: Kagawa failed to impress David Moyes during his tenure at Manchester United

Surplus: Kagawa (second left) does not fit in under Louis van Gaal's new system and has been allowed to leave

German success: Kagawa holds the German cup after Dortmund's victory against Bayern Munich in 2012